DeviceNet Slave Communication Module IFD9502 z Common Services 3. Format of inquiries and messages responded z IFD9502 allows you to inquire PLC by explicit messages. The format of inquiry is shown in the table below. z Explanation „ “Position address” refers to the No. of the device in the register of PLC. For example, the position address of M0 is 0 and that of D100 is 100. „ “Number” refers to the number of PLCs. When the read device is a word device, “Number” refers to the number of words read; when the read device is a bit device, “Number” refers to „ Bit devices, S, X, Y and M in DVP-PLC allow the reading of maximum 16 bits and writing in the number of bits read.
of only 1 bit (either 0 or 1). Devices T, C and D in DVP-PLC allow the reading of maximum 3 words and writing in of 1 word. See the table below. DVP-PLC Application Manual 11 Service code Implemented for Service name Class Instance 0x32 No Yes Read PLC data 0x33 No Yes Write PLC data Byte position Data read from PLC Data written into PLC 0 Frag [0]+XID+MAC ID Frag [0]+XID+MAC ID 1 R/R [0]+Service code [0x32] R/R [0]+Service code [0x33] 2 Class ID [0x96] Class ID [0x96] 3 Instance ID Instance ID 4 Position address LSB Position Address LSB 5 Position address MSB Position Address MSB 6 Number LSB Service data LSB 7 Number MSB Service data MSB Device in PLC Max. length to be read allowed Max.
length to be written in allowed S 16 bits 1 bit X 16 bits Not support Y 16 bits 1 bit M 16 bits 1 bit T (bit device) 16 bits 1 bit C (bit device) 16 bits 1 bit T (word device) 3 words 1 word C (word device) 3 words 1 word D (word device) 3 words 1 word