User manual HANNA INSTRUMENTS HI 710

[. . . ] HI 700 / HI 710 Series Process, Panel-mounted, Microprocessor-based, Conductivity and TDS Controllers Instruction Manual Dear Customer, Thank you for choosing a Hanna Product. This instruction manual has been written for the following products: HI 700221- EC controller with dual setpoint, ON/OFF and PID controls, analog output. HI 700222- EC controller with dual setpoint, ON/OFF and PID controls, RS485 port. HI 710221- EC and TDS controller with dual setpoint, ON/OFF and PID controls, analog output. [. . . ] HI 92500 makes it possible for you to use the powerful means of the most diffused spreadsheet programs (Excel©, Lotus 1-2-3© etc. ). Simply run your favorite spread sheet and open the file downloaded by HI 92500. To install HI 92500 you need a 3. 5" drive and few minutes to follow the instructions conveniently printed on the disk's label. SPECIFICATIONS The RS485 standard is implemented in with the following characteristics: Data rate: up to 9600 bps Communication: Bi-directional Half-Duplex Line length: up to 1. 2 Km typ. Internal termination: none Note The analog output is factory calibrated through software. The user may also perform the calibration procedure as explained in the following. It is recommended to perform the output calibration at least once a year. The analog output is "frozen" when entering the setup or calibration mode (after password confirmation). Note Note Excel© Copyright of "Microsoft Co. " Lotus 1-2-3© Copyright of "Lotus Co. " Windows® registered Trademark of "Microsoft Co. " 28 29 CONNECTIONS The connections for the 6-pin RS485 terminal provided (#1 on page 7) are as follows: As additional feature, the controller is also provided with two pins (5V and 0V) in order to apply the Fail Safe Open Line protection method. To avoid erroneous readings in Open-Line conditions, pullup and pull-down resistors should be connected as shown. The Fail-Safe resistors are connected only to one unit in the line, and their value depends on the application and characteristic impedance of the connection cable. There is an internal short between the two A pins and between the two B pins. To terminate the line, an external resistor equal to the characteristic line impedance (typically 120) must be added at both ends of the line. The RS485 port is optoisolated from measuring circuit and power line. RS485 PROTOCOL The commands sent to the controller must have the following format: · 2-digit process ID number · 3-character command name · Parameters (variable length, may be null) · End of command (always the CR character, Hex 0D) A maximum time interval of 20 ms is allowed between two consecutive characters of a command. Up to 32 units can be connected to the same RS485 line, with a total line length of up to 1. 2 Km using 24AWG cable. To minimize electromagnetic interferences, use shielded or twisted pair cable to connect the units. Each unit is identified by its process ID number (setup item "01"). The controller acts as a "slave" device: it only answers to commands received from a "master" device (e. g. an industrial PC) connected to the line. It is possible to send commands to change the controller settings or to simply ask information on the controller status. Following is the complete list of commands available: 30 31 Command CAR GET K 01 K 02 KCD KCF KCL KDS KDW KRG KST KUP MDR ECR TDR Parameter null NN null null null null null null null null null null null null null Description Request calibration data Request setup item NN Same as CFM+ +CAL keys Same as LCD+CAL+SETUP keys Same as CAL DATA key Same as CFM key Same as CAL key Same as LCD key Same as Same as key key Note If the controller is not in control or idle mode and the temperature reading is requested through the TMR command, the controller answers with the last acquired reading when it was in control or idle mode. After a recognized PWD command is received, the controller allows a maximum of 1 minute without receiving data, after which it locks again and a new PWD command is needed to perform password protected operations. Following are examples of commands for setup items: 1) "03 SET 22-01200<CR>" This command sets the setup item 22 (relay 2 setpoint) of a EC controller, identified by the process ID number 03, to the +12. 00 mS value. 2) "01 SET 33+005 <CR>" This command sets the setup item 33 (max. relay ON time) of a controller, identified by the process ID number 01, to 5 minutes. Once the controller has received a command, it answers with its 2-digit process ID number followed by: · ACK (Hex 06) If the controller recognizes the received command and performs the requested task; · STX (Hex 02) , Data , ETX (Hex 03) If the received command is a request of data; · NAK (Hex 15) If the received command is not recognized (e. g. [. . . ] The time interval is programmable in number of days through setup code 72. This output is ON for the period set through setup code 77 (this period can be also changed when the output is ON). The starting time of the cleaning timer can be set through setup codes 73, 74, 75 and 76. 48 49 EC VALUES AT VARIOUS TEMPERATURES Temperature has a significant effect on conductivity. Table below shows EC values at various temperatures for the Hanna calibration solutions. [. . . ]