No. SS2-AVP703-0100 Azbil Corporation - 4 - FIELDBUS SPECIFICATIONS Function Blocks VCR Structure The AVP has 32 VCRs (Virtual Communication Relationships), of which the first one is dedicated to the SMIB/NMIB defined by the Foundation Fieldbus specifications. The rest of the VCRs are fully configurable. Network Parameters The following table shows the key parameter values that affect interoperability of the Fieldbus devices. The LAS needs to be configured to satisfy these parameters. If other devices on the same Fieldbus network require a greater number for them, the greater number must be used. This will degrade network performance, though. Block name Number Period of execution (ms) Note AO 1 30 For Set Point DI 2 30 For limit switches AR 1 30 Arithmetic block perform an arithmetical operation to the process measurement value. PID 2 45 PID function block execute a control algorithm to minimize the error as the difference between a measured process variable and desired set-point. It also has functions of cascade control, feed forward control, and alarm detection. OS 1 30 Output splitter block perform the sprit control operation. IS 1 30 Input selector block perform the control of select the process value. VCR No. Configuration 1 QUB (Server) for NMIB/SNIB 2-32 Fully configurable Symbol Parameter Factory Setting Range of Value V (ST) Slot Time *1 5 5 to 100 V (MID) Minimum Inter PDU Delay *1 10 10 to (V(MRD)-1)×V(ST), smaller than 120 inclusive. V (MRD) Maximum Response Delay *2 4 V(MRD)×V(ST) shall be greater than 20 and V(MRD) shall be smaller than 11, inclusive. T1 SM Step Timer 48000 (15 seconds) --- T2 SM Set Address Sequence Timer 2880000 (90 seconds) T2 > T3 T3 SM Set Address Wait Timer 1440000 (45 seconds) T2 > T3 V (FUN) First Unpolled Node 0x25 0x14 to 0xF7 V (NUN) Number of consecutive Unpolled-Node 0xBA 0x00 to oxE4 V(MSO) Maximum Scheduling Overhead *1 0x00 0x00 to 0x 3F V(DMDT) Default Minimum Token Delegation time *1 0x56 0x20 to 0x7FFF V(DTHT) Default Token Holding Time *1 0x0400 0x0114 to 0xFDE8 (65,000) V(TTRT) Target Token Rotation Time *1 4096 1 to 60000ms V(LTHT) Link Maintenance Token Holding Time *1 0x0124 0x0124 to 0xFDE8 (65,000) V(TDP) Time Distribution Period 5000 5 to 55000ms V(MICD) Maximum Inactivity to Claim LAS Delay *1 2000 1 to 4095 V(LDDP) LAS Database Distribution Period 3000 100 to 55000ms