Table of Contents
Modbus for Grundfos pumps
The system diagrams provide an overview of the different technologies and how to connect the module or unit to the Grundfos E pump that you connect to a Modbus network.
With Modbus cards, the pumps can be controlled from the monitoring system (or from PLC), and all technical parameters are available from the units.
CIU solution
The Communication Interface Unit (CIU) is a box with a power supply module and a CIM Modbus module. You can mount either on
a DIN rail or on a wall.
You use it in conjunction with Grundfos E-pumps that do not support an internal, add-on communication module, CIM.
CIM solution
The Communication Interface Module (CIM) is an add-on communication module you install internally in a Grundfos E-pump using a 10-pin connection. In this setup, the E-pump will
supply power to CIM 200.
For mounting of the CIM add-on module, see the installation and operating instructions for the E-pump in question.
CIM 200 Modbus RTU
| Modbus RTU specifications | Description | Comments |
|---|---|---|
| Modbus connector | Screw-type terminal | 3 pins |
| Modbus connection type | RS-485, 2-wire + common | Conductors: D0, D1 and Common |
| Maximum cable length | 1200 m | Equals 4000 ft |
| Slave address | 1-247 | Set via rotary switches SW6 and SW7 |
| Line termination | On or Off | Set via DIP switches SW1 and SW2 |
| Recommended cable cross-section | 0.20 - 0.25 mm2 | AWG24 or AWG23 |
| Supported transmission speeds | 1200 1), 2400 1), 4800 1), 9600, 19200, 38400 bit/s | Set via DIP switches SW4 and SW5 |
| Start bit | 1 | Fixed value |
| Data bits | 8 | Fixed value |
| Stop bits | 1 or 2 | Set via DIP switch SW3 |
| Parity bit | Even parity, odd parity 1) or no parity | Set via DIP switch SW3 |
| Modbus visual diagnostics | LED1 | Off, flashing green, flashing red, permanently red |
| Maximum number of Modbus devices | 32 | Using repeaters, you can increase this number.Legal address range is 1-247 |
| Maximum Modbus telegram size | 256 bytes | Total length. Node address and CRC included |
Application example
Through the CIM 200 module, the Grundfos pump can be controlled directly from the various controllers, and all its parameters can be read. These parameters can be displayed, for example, on HMI or SCADA. The Ethernet / RS485 converter converts TCP telegrams into RTU form and transmits them as such. Thanks to this unit, the connection can serve several master units (multimaster). The video below shows (and hears) the operation of the first Labview test program. This is just a test program I wrote to test the connection, not a particularly spectacular application.
First Labview testprogram for Grundfos CIM 200 modul
Related links:
CIM 260 3G/4G cellular Modbus
| Modbus cellular specifications | Description | Comments |
|---|---|---|
| Data protocol | Modbus TCP | Data connection uses Modbus TCP |
| Slave address | Factory 231 (0xE7) | You can change the address via Modbus register 00003, SoftwareDefinedModbusAddress |
| Cellular connection visual diagnostics | LED1 | |
| Maximum Modbus telegram size | 260 bytes | Total Modbus TCP/IP application data unit |
CIM 500 Modbus TCP
| Modbus TCP specifications | Description | Comments |
|---|---|---|
| Application layer | DHCP, HTTP, Ping, FTP, Modbus TCP | Rotary switch in position 1 to select Modbus TCP |
| Transport layer | TCP | |
| Internet layer | Internet protocol V4 (IPv4) | |
| Link layer | ARP, media access control (Ethernet) | |
| Ethernet cable | CAT5, CAT5e or CAT6 | Supports auto cable-crossover detecting (Auto-MDIX) |
| Maximum cable length | 100 metres | Corresponds to 328 feet |
| Transmission speed | 10 Mbit/s, 100 Mbit/s | Auto-detected |
Application example
Through the CIM 500 module, the Grundfos pump can be directly controlled from the S7-1500 PLC, and all its parameters can be read. These parameters can be displayed, for example, on HMI or SCADA.
Modbus structure (registers)
See it: Grundfos download Grundfos Modbus specification, 18 Mbyte
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