Special Relay Comparison Table by Manufacturer
A cross-reference table that lines up devices with the same purpose or similar names: the special relays (SM) and special registers (SD) of the Mitsubishi MELSEC iQ-R, the control relays (CR) and control memory (CM) of the KEYENCE KV-8000, and the Auxiliary Area (A) and condition flags of the OMRON CJ2. Use it as a reference when migrating between models or writing programs for multi-vendor systems.
Date/time and day of week
| Device name | Mitsubishi iQ-R | KEYENCE KV-8000 | OMRON CJ2 | Remarks |
|---|---|---|---|---|
| Clock data: year | SD210 (YYYY BIN) | CM0700 (YY BIN) | A353.08-15 (YY BCD) | |
| Clock data: month | SD211 | CM0701 | A353.00-07 (BCD) | |
| Clock data: day | SD212 | CM0702 | A352.08-15 (BCD) | |
| Clock data: hour | SD213 | CM0703 | A352.00-07 (BCD) | |
| Clock data: minute | SD214 | CM0704 | A351.08-15 (BCD) | |
| Clock data: second | SD215 | CM0705 | A351.00-07 (BCD) | |
| Clock data: day of week | SD216 | CM0706 | A354.00-07 | 0=Sun to 6=Sat |
CPU status
| Device name | Mitsubishi iQ-R | KEYENCE KV-8000 | OMRON CJ2 | Remarks |
|---|---|---|---|---|
| RUN/STOP switch status | SD200 (0=RUN 1=STOP) | CR3904 (0=PRG 1=RUN) | — | Opposite polarity |
| STOP contact | SM203 (1=STOP) | — | — | |
| PAUSE contact | SM204 (1=PAUSE) | — | — | |
| CPU firmware / function version | SD160 | CM0900 (HEX) | — |
Scan time
| Device name | Mitsubishi iQ-R | KEYENCE KV-8000 | OMRON CJ2 | Remarks |
|---|---|---|---|---|
| Current scan time | SD520 (ms part) SD521 (μs part) | CM1000-CM1001 (μs 32bit) | A264-A265 (0.1ms) | |
| Current scan time | A266-A267 (0.01ms) | |||
| Minimum scan time | SD522 (ms part) SD523 (μs part) | CM1004-CM1005 | — | |
| Maximum scan time | SD524 (ms part) SD525 (μs part) | CM1006-CM1007 (μs 32bit) | A262-A263 (0.1ms) | |
| END processing time | SD526 (ms part) SD527 (μs part) | CM1002-CM1003 (μs 32bit) | — | |
| Clear min/max scan time | SM522 | CR2307 | — |
Always ON, always OFF, clock pulses
| Device name | Mitsubishi iQ-R | KEYENCE KV-8000 | OMRON CJ2 | Remarks |
|---|---|---|---|---|
| Always ON | SM400 | CR2002 | P_On | |
| Always OFF | SM401 | CR2003 | P_Off | |
| ON for 1 scan only after RUN | SM402 | CR2008 | P_First_Cycle | |
| OFF for 1 scan only after RUN | SM403 | CR2007 | — | |
| 0.1 ms clock | — | — | P_0_1ms | |
| 1 ms clock | — | — | P_1ms | |
| 10 ms clock | SM409 | CR2004 | P_0_01s | |
| 20 ms clock | — | — | P_0_02s | |
| 100 ms clock | SM410 | CR2005 | P_0_1s | |
| 200 ms clock | SM411 | — | P_0_2s | |
| 1 s clock | SM412 | CR2006 | P_1s | |
| 2 s clock | SM413 | — | — | |
| 1 min clock | — | — | P_1min | |
| 2n s clock | SM414 | — | — | |
| 2n ms clock | SM415 | — | — | |
| 0.1 μs free-running counter | — | CM1036-CM1037 (32bit) | — | |
| 1 μs free-running counter | — | CM1034-CM1035 (32bit) | — | |
| 10 μs free-running counter | — | CM1032-CM1033 (32bit) | — | |
| 1 ms free-running counter | — | CM1030-CM1031 (32bit) | — | |
| 10 ms free-running counter | — | — | A0 (16bit) | |
| 100 ms free-running counter | — | — | A1 (16bit) | |
| 1 s free-running counter | SD412 (16bit) | — | A2 (16bit) | |
| 2n s counter | SD414 | — | — | |
| 2n ms counter | SD415 | — | — | |
| Scan counter | SD420 | — | — |
Operations and instructions
| Device name | Mitsubishi iQ-R | KEYENCE KV-8000 | OMRON CJ2 | Remarks |
|---|---|---|---|---|
| Instruction execution error (operation error) | SM56 | CR2012 | P_ER | |
| Self-diagnostic error code | SD0 | — | — | |
| Operation error details | — | CM0712 | — | |
| Carry flag / operation result flag | SM700 | — | P_CY | |
| Operation result negative or overflow | — | CR2009 | — | |
| Operation result zero | — | CR2010 | — | |
| Operation result positive | — | CR2011 | — | |
| > flag | — | — | P_GT | |
| = flag | — | — | P_EQ | |
| < flag | — | — | P_LT | |
| Negative flag | — | — | P_N | |
| Overflow | — | — | P_OF | |
| Underflow | — | — | P_UF | |
| >= flag | — | — | P_GE | |
| NOT= flag | — | — | P_NE | |
| <= flag | — | — | P_LE |
Errors
| Device name | Mitsubishi iQ-R | KEYENCE KV-8000 | OMRON CJ2 | Remarks |
|---|---|---|---|---|
| Self-diagnostic error occurred | SM0 | CR3905 (major error) | A401.xx (fatal error) | |
| Self-diagnostic error occurred (minor error) | CR3906 (minor error) | A402.xx (non-fatal error) | ||
| Latest error code | SD0 | CM5105 (major error) | A400 | |
| Time of latest error | SD1-SD7 | CM5100-CM5104 (major error) | A100-A199 (error log) | |
| Latest error code (minor error) | CM5155 (minor error) | |||
| Time of latest error (minor error) | CM5150-CM5154 (minor error) | |||
| Error reset | SM50 | CR3909 | FAL instruction | |
| Clear major error history | — | CR3900 | — | |
| Clear minor error history | — | CR3901 | — | |
| Clear all error and event history | — | CR3910 | A500.14 | |
| Low battery | SM51 (latched) SM52 | CR2306 | A402.04 | |
| Annunciator detection / alarm operation | SM62 | CR3300-CR3415 (alarm relays) CR3500 (alarm operation) | A360-A391 (FAL) A402.15 (FAL error) | |
| Inter-module synchronization error | SM480 / SM488 | CR3100 | A10101 (WORD) |
Storage
| Device name | Mitsubishi iQ-R | KEYENCE KV-8000 | OMRON CJ2 | Remarks |
|---|---|---|---|---|
| Memory card usable (recognition complete) | SM600 | CR5403 | A343.15 | |
| Memory card write-protected | SM601 | CR5405 | A343.09 (write disabled) | |
| Memory card inserted | SM603 | CR5404 | A343.00-02 (4 = flash ROM) | |
| Memory card in use | SM604 | CR5402 | A343.13 | |
| Memory card unmount | SM606 (ON = release request) | CR5401 (unmount request) | — | |
| Memory card disabled state | SM607 | (CR5403 OFF) | — | |
| File access in progress | SM753 | CR3214 | A343.14 |
Logging and tracing
| Device name | Mitsubishi iQ-R | KEYENCE KV-8000 | OMRON CJ2 | Remarks |
|---|---|---|---|---|
| Logging start / execute | SM1211 (ID2～ SM1220～) | CR0000 (ID2～ CR100～) | — | |
| Data trace start | — | — | A508.15 | |
| Logging in progress (collecting) | SM1212 | CR0001 | A508.13 (trace in progress) | |
| Logging complete (file write finished) | SM1213 | CR0002 | A508.12 (trace completed) | |
| Trigger | SM1214 | CR0011 | A508.14 (trace trigger) | |
| Logging error | SM1216 | CR0008 | — | |
| Logging processing overrun | SD1215 (count) | CR0004 (occurrence bit) | — | |
| Free space in internal buffer | SD1214 (Kbyte) | CM1660 ID0 -CM1669 ID9 (Kbyte) | — | |
| Saved file number / counter | SD1210-SD1211 | CM1500 ID0 -CM1509 ID9 | — | |
| Logging ID 2 to 9 | SM1220～SM1309 SD1220～SD1307 |
Power supply
| Device name | Mitsubishi iQ-R | KEYENCE KV-8000 | OMRON CJ2 | Remarks |
|---|---|---|---|---|
| Number of power interruptions (momentary) | SD53 | — | A514 |
Source
- Mitsubishi Electric MELSEC iQ-R CPU Module User's Manual (Application), Appendix 4 List of Special Relay Areas / Appendix 5 List of Special Register Areas
- KEYENCE KV-8000 Series User's Manual, A-10 to A-17 (CR/CM list)
- OMRON CJ Series CJ2 CPU Unit Software User's Manual (SBCA-350), A-3 Auxiliary Area list
Check actual behavior in each manufacturer's manual.
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