2 Functions of Devices in DVP-PLC Function Group Monitor Timer Number D1000 Contents: 1. Monitor timer is used for monitoring PLC scan time. When the scan time exceeds the set time in the monitor timer, the red ERROR LED indicator remains beaconing and all outputs will be “Off”. 2. The initial set value of the time in the monitor timer is 200ms. If the program is long or the operation is too complicated, MOV instruction can be used for changing the set value. See the example below for SV = 300ms. M1002 0 Initial pulse 3. The maximum set value in the monitor timer is 32,767ms. Please be noted that if the SV is too big, the timing of detecting operational errors will be delayed.
Therefore, it is suggested that you remain the scan time of shorter than 200ms. 4. Complicated instruction operations or too many extension modules being connected to the MPU will result in the scan time being too long. Check D1010 ~ D1012 to see if the scan time exceeds the SV in D1000. In this case, besides modifying the SV in D1000, you can also add WDT instruction (API 07) into the PLC program. When the CPU execution progresses to WDT instruction, the internal monitor timer will be cleared as “0” and the scan time will not exceed the set value in the monitor timer. Function Group Program Capacity Number D1002 Contents: The program capacity differs in different series of MPUs. 1.
ES/EX/SS series MPU: 3,792 steps 2. SA/SC series MPU: 7,920 steps 3. SX series MPU: 7920 steps (There are 15872 steps in SX V3.0 or above.) 4. EH2/SV series MPU: 15,872 steps 5. EH3/SV2 series MPU: 30000 steps Function Group Syntax Check Number M1004, D1004, D1137 Contents: 1. When errors occur in syntax check, ERROR LED indicator will flash and special relay M1004 = On. 2. Timings for PLC syntax check: a) When the power goes from “Off” to “On”. b) When the program is written into PLC by means of WPLSoft, ISPSoft or HPP. c) When on-line editing is being conducted. 3. The syntax check may start due to illegal use of instruction operands (devices) or incorrect program syntax loop.
The error can be detected by the error code in D1004 and error table. The address where the error exists will be stored in D1137. (The address value in D1137 will be invalid if the error is a general loop error.) DVP-PLC Application Manual 2-72 MOV K300 D1000