PLC INSTRUCTIONS DELTA PLC The model I’m still using is DVP 14 SS series, which has 8
inputs and 6 outputs. The communication cable used to download and upload the program is RS232. The inputs may be switches, sensors, push buttons, limit switch etc. And outputs may be indicator, motors, relays, valves, connectors etc. X0-x7 are the inputs in DVP 14SS series PLC Y0-y5 are the outputs in DVP 14SS series PLC 1> LD – to load the open contact. E.g. LD x0 2> LDI- to load the close contact. E.g. LDI x0 3> OUT- to select the coil. E.g. OUT y0 4> SET- to set the coil permanently. E.g. SET y0 5> RST- to reset the coil from set state. E.g. RST y0 These are the general instructions used in PLC.
1> Timers and counters: Timers and counters are used for the continuous operation in the PLC. Timers times up to the value set by the user and counter counts up to the value set by the user. Both are of 16 bit.
TIMER: Timer is off two types: We have 127 timers (T127) in DELTA PLC. Retentive and Non retentive And under these two types, timer is divided as On-delay timer and off- delay timer. Timer base = 10ms. For setting 10 sec, timer is set as, 10*10= 100ms or 10 sec.
Timer syntax: TMR T0 K100 (10 secs). Here TMR is command, T0 is timer number, K is constant and 100 set value set by user, which is 10 sec, means timer will times up to 10 seconds.
COUNTER: Counter syntax: CNT C0 K5 Here CNT is command, C0 is counter number, K is constant and 5 is value set by user, which is 5, means counter will counts up to 5 times.
2> DATA REGISTERS: Data registers are used to store the numerical values and are off 16-bit. Data registers are divided up to D0-D599. Data registers are used to vary
the constant values in timers and counters. D0-D407 – They are general purpose registers and have volatile memory. It only stores the data when the PLC is in running mode, as the PLC stops the stored data erased.
D408-D599- They are latched purpose registers and have nonvolatile memory. It stores the data permanently even when the PLC is stopped.
3> INCREMENT/DECREMENT: Increment is used for +1 and decrement is used for -1. Syntax: INC D0, means data register (D0) is increased by 1 And DEC D0, means data register (D0) is decreased by 1.
4> MOVE INSTRUCTION: It is the data transfer instruction to move the data from source to destination.
I.e. MOVE source destination. Syntax: MOV S D S is the constant data register and D is the variable data register.
5> RISING/FALLING EDGES: The clock moving from 1 to 0 is the rising edge and clock moving from 0 to 1 is falling
edge. It remains constant throughout the instruction. Syntax: LDP x0. For rising edge. LDF x0. For falling edge.
6> ARITHMATIC INSTRUCTIONS: Addition subtraction multiplication and divide are the arithmetic instructions. Syntax: ADD S1 S2 D0. To add two source registers (S1, S2) and stores result in data register (D0). SUB S1 S2 D1. To subtract two source registers (S1, S2) and stores the result in data register (D1). MUL S1 S2 D2. To multiply two source registers (S1, S2) and stores the result in data register (D2).
DIV S1 S2 D3. To divide source registers (S1, S2) and stores the result in data register (D3).
7> COMPARE INSTRUCTIONS: These are used to compare two inputs. AB- greater than. Syntax: LD> A B A=!B- not equal to. Syntax: LD<> A B
8> ZONE COMPARE: Zone compare is used to compare the two values. Syntax: ZCP K3 K6 D0 M1.
9> ZONE RESET: Zone reset is used to reset the values of a zone. Syntax: ZRST Y0 Y3. Here Y0-Y3 is a zone.
10> MEMORY BITS: M1000: Remains ON during entire cycle.
M1001: Remains OFF during entire cycle. M1011: Remains ON/OFF for 5ms. Total cycle is 10ms. M1012: Remains ON/OFF for 50ms. Total cycle is 100ms. M1013: Remains ON/OFF for 0.5ms. Total cycle is 1sec. M1014: Remains ON/OFF for 30s. Total cycle is 1min.
