4 Step Ladder Instructions Restrictions on Divergence Sequence: 1. You can use maximum 8 divergence steps in a divergence sequence. As the diagram below, there are maximum 8 diverged steps S30 ~ S37 after step S20. 2. You can use maximum 16 loops in multiple divergence sequences or in simultaneous sequences combined into one sequence. As the diagram below, there are 4 steps diverged after S40, 7 steps diverged after S41, and 5 steps diverged after S42. There are maximum 16 loops in this sequence. 3. You can designate a step in the sequence to jump to any step in another sequence.
M1002 X0 S20 S0 Y0 X1 S30 Y1 X2 S31 Y2 X3 S32 Y3 X4 S35 Y6 S36 X7 Y7 X10 S37 Y10 X20 X11 S40 Y11 X12 S0 SET X13 S20 OUT X14 X15 S41 Y12 X16 S36 RST X17 X25 S42 Y13 X32 S50 Y14 X33 S51 Y15 X34 S52 Y16 S20 OUT X21 S53 Y17 S54 Y20 X22 S55 Y21 S56 Y22 S57 Y23 S20 X23 OUT X37 X24 S58 RST Y24 X40 S59 Y25 X26 X41 Y26 S60 X27 X42 Y27 S61 X30 Y30 S62 X31 Y31 S63 X44 S70 Y32 S71 Y33 S72 Y34 X35 X45 S73 Y35 X36 X46 S74 Y36 S58 X47 S75 S0 OUT SET Y37 X43 X50 Y40 S76 X51 S80 Y41 S0 SET X52 S81 Y42 S42 S0 SET 4.6 IST Instruction Operands: S : Start device in the designated operation mode D 1 : The smallest No. of designated step in auto mode D 2 : The biggest No.
of designated step in auto mode Explanations: 1. S will occupy 8 consecutive points. 2. Range of D 1 and D 2 : for SA/SX/SC/EH2/SV/EH3/SV2 S20 ~ S899; for ES/EX/SS S20 ~ S127; D 2 > D 1 . 3. See the specifications of each model for their range of use. 4. IST instruction can only be used once in the program. 5. Flags: M1040 ~ M1047. See remarks for more details. 6. IST instruction is a handy instruction specifically for the initial status of step ladder control procedure to accommodate special auxiliary relay.
DVP-PLC Application Manual 4-19 X S32 Y4 5 X6 S34 Y5 S API Mnemonic Operands Function IST Initial State Type OP Bit Devices Word Devices Program Steps X Y M S K H KnX KnY KnM KnS T C D E F IST: 7 steps S * * * D 1 * D 2 * PULSE 16-bit 32-bit ES EX SS SA SX SC EH2 SV EH3 SV 2 ES EX SS SA SX SC EH2 SV EH3 SV2 ES EX SS SA SX SC EH2 SV EH3 SV2